#ifndef INCLUDE_LLHTTP_H_
#define INCLUDE_LLHTTP_H_

#define LLHTTP_VERSION_MAJOR 2
#define LLHTTP_VERSION_MINOR 0
#define LLHTTP_VERSION_PATCH 1

#ifndef INCLUDE_LLHTTP_ITSELF_H_
#define INCLUDE_LLHTTP_ITSELF_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>

typedef struct llhttp__internal_s llhttp__internal_t;
struct llhttp__internal_s
{
    int32_t _index;
    void* _span_pos0;
    void* _span_cb0;
    int32_t error;
    const char* reason;
    const char* error_pos;
    void* data;
    void* _current;
    uint64_t content_length;
    uint8_t type;
    uint8_t method;
    uint8_t http_major;
    uint8_t http_minor;
    uint8_t header_state;
    uint16_t flags;
    uint8_t upgrade;
    uint16_t status_code;
    uint8_t finish;
    void* settings;
};

int llhttp__internal_init(llhttp__internal_t* s);
int llhttp__internal_execute(llhttp__internal_t* s, const char* p, const char* endp);

#ifdef __cplusplus
}  /* extern "C" */
#endif
#endif  /* INCLUDE_LLHTTP_ITSELF_H_ */

#ifndef LLLLHTTP_C_HEADERS_
#define LLLLHTTP_C_HEADERS_
#ifdef __cplusplus
extern "C" {
#endif

enum llhttp_errno
{
    HPE_OK = 0,
    HPE_INTERNAL = 1,
    HPE_STRICT = 2,
    HPE_LF_EXPECTED = 3,
    HPE_UNEXPECTED_CONTENT_LENGTH = 4,
    HPE_CLOSED_CONNECTION = 5,
    HPE_INVALID_METHOD = 6,
    HPE_INVALID_URL = 7,
    HPE_INVALID_CONSTANT = 8,
    HPE_INVALID_VERSION = 9,
    HPE_INVALID_HEADER_TOKEN = 10,
    HPE_INVALID_CONTENT_LENGTH = 11,
    HPE_INVALID_CHUNK_SIZE = 12,
    HPE_INVALID_STATUS = 13,
    HPE_INVALID_EOF_STATE = 14,
    HPE_CB_MESSAGE_BEGIN = 15,
    HPE_CB_HEADERS_COMPLETE = 16,
    HPE_CB_MESSAGE_COMPLETE = 17,
    HPE_CB_CHUNK_HEADER = 18,
    HPE_CB_CHUNK_COMPLETE = 19,
    HPE_PAUSED = 20,
    HPE_PAUSED_UPGRADE = 21,
    HPE_USER = 22
};
typedef enum llhttp_errno llhttp_errno_t;

enum llhttp_flags
{
    F_CONNECTION_KEEP_ALIVE = 0x1,
    F_CONNECTION_CLOSE = 0x2,
    F_CONNECTION_UPGRADE = 0x4,
    F_CHUNKED = 0x8,
    F_UPGRADE = 0x10,
    F_CONTENT_LENGTH = 0x20,
    F_SKIPBODY = 0x40,
    F_TRAILING = 0x80,
    F_LENIENT = 0x100
};
typedef enum llhttp_flags llhttp_flags_t;

enum llhttp_type
{
    HTTP_BOTH = 0,
    HTTP_REQUEST = 1,
    HTTP_RESPONSE = 2
};
typedef enum llhttp_type llhttp_type_t;

enum llhttp_finish
{
    HTTP_FINISH_SAFE = 0,
    HTTP_FINISH_SAFE_WITH_CB = 1,
    HTTP_FINISH_UNSAFE = 2
};
typedef enum llhttp_finish llhttp_finish_t;

enum llhttp_method
{
    HTTP_DELETE = 0,
    HTTP_GET = 1,
    HTTP_HEAD = 2,
    HTTP_POST = 3,
    HTTP_PUT = 4,
    HTTP_CONNECT = 5,
    HTTP_OPTIONS = 6,
    HTTP_TRACE = 7,
    HTTP_COPY = 8,
    HTTP_LOCK = 9,
    HTTP_MKCOL = 10,
    HTTP_MOVE = 11,
    HTTP_PROPFIND = 12,
    HTTP_PROPPATCH = 13,
    HTTP_SEARCH = 14,
    HTTP_UNLOCK = 15,
    HTTP_BIND = 16,
    HTTP_REBIND = 17,
    HTTP_UNBIND = 18,
    HTTP_ACL = 19,
    HTTP_REPORT = 20,
    HTTP_MKACTIVITY = 21,
    HTTP_CHECKOUT = 22,
    HTTP_MERGE = 23,
    HTTP_MSEARCH = 24,
    HTTP_NOTIFY = 25,
    HTTP_SUBSCRIBE = 26,
    HTTP_UNSUBSCRIBE = 27,
    HTTP_PATCH = 28,
    HTTP_PURGE = 29,
    HTTP_MKCALENDAR = 30,
    HTTP_LINK = 31,
    HTTP_UNLINK = 32,
    HTTP_SOURCE = 33
};
typedef enum llhttp_method llhttp_method_t;

#define HTTP_ERRNO_MAP(XX) \
    XX(0, OK, OK) \
    XX(1, INTERNAL, INTERNAL) \
    XX(2, STRICT, STRICT) \
    XX(3, LF_EXPECTED, LF_EXPECTED) \
    XX(4, UNEXPECTED_CONTENT_LENGTH, UNEXPECTED_CONTENT_LENGTH) \
    XX(5, CLOSED_CONNECTION, CLOSED_CONNECTION) \
    XX(6, INVALID_METHOD, INVALID_METHOD) \
    XX(7, INVALID_URL, INVALID_URL) \
    XX(8, INVALID_CONSTANT, INVALID_CONSTANT) \
    XX(9, INVALID_VERSION, INVALID_VERSION) \
    XX(10, INVALID_HEADER_TOKEN, INVALID_HEADER_TOKEN) \
    XX(11, INVALID_CONTENT_LENGTH, INVALID_CONTENT_LENGTH) \
    XX(12, INVALID_CHUNK_SIZE, INVALID_CHUNK_SIZE) \
    XX(13, INVALID_STATUS, INVALID_STATUS) \
    XX(14, INVALID_EOF_STATE, INVALID_EOF_STATE) \
    XX(15, CB_MESSAGE_BEGIN, CB_MESSAGE_BEGIN) \
    XX(16, CB_HEADERS_COMPLETE, CB_HEADERS_COMPLETE) \
    XX(17, CB_MESSAGE_COMPLETE, CB_MESSAGE_COMPLETE) \
    XX(18, CB_CHUNK_HEADER, CB_CHUNK_HEADER) \
    XX(19, CB_CHUNK_COMPLETE, CB_CHUNK_COMPLETE) \
    XX(20, PAUSED, PAUSED) \
    XX(21, PAUSED_UPGRADE, PAUSED_UPGRADE) \
    XX(22, USER, USER) \


#define HTTP_METHOD_MAP(XX) \
    XX(0, DELETE, DELETE) \
    XX(1, GET, GET) \
    XX(2, HEAD, HEAD) \
    XX(3, POST, POST) \
    XX(4, PUT, PUT) \
    XX(5, CONNECT, CONNECT) \
    XX(6, OPTIONS, OPTIONS) \
    XX(7, TRACE, TRACE) \
    XX(8, COPY, COPY) \
    XX(9, LOCK, LOCK) \
    XX(10, MKCOL, MKCOL) \
    XX(11, MOVE, MOVE) \
    XX(12, PROPFIND, PROPFIND) \
    XX(13, PROPPATCH, PROPPATCH) \
    XX(14, SEARCH, SEARCH) \
    XX(15, UNLOCK, UNLOCK) \
    XX(16, BIND, BIND) \
    XX(17, REBIND, REBIND) \
    XX(18, UNBIND, UNBIND) \
    XX(19, ACL, ACL) \
    XX(20, REPORT, REPORT) \
    XX(21, MKACTIVITY, MKACTIVITY) \
    XX(22, CHECKOUT, CHECKOUT) \
    XX(23, MERGE, MERGE) \
    XX(24, MSEARCH, M-SEARCH) \
    XX(25, NOTIFY, NOTIFY) \
    XX(26, SUBSCRIBE, SUBSCRIBE) \
    XX(27, UNSUBSCRIBE, UNSUBSCRIBE) \
    XX(28, PATCH, PATCH) \
    XX(29, PURGE, PURGE) \
    XX(30, MKCALENDAR, MKCALENDAR) \
    XX(31, LINK, LINK) \
    XX(32, UNLINK, UNLINK) \
    XX(33, SOURCE, SOURCE) \



#ifdef __cplusplus
}  /* extern "C" */
#endif
#endif  /* LLLLHTTP_C_HEADERS_ */

#ifndef INCLUDE_LLHTTP_API_H_
#define INCLUDE_LLHTTP_API_H_
#ifdef __cplusplus
extern "C" {
#endif
#include <stddef.h>

typedef llhttp__internal_t llhttp_t;
typedef struct llhttp_settings_s llhttp_settings_t;

typedef int (*llhttp_data_cb)(llhttp_t*, const char* at, size_t length);
typedef int (*llhttp_cb)(llhttp_t*);

struct llhttp_settings_s
{
    /* Possible return values 0, -1, `HPE_PAUSED` */
    llhttp_cb      on_message_begin;

    llhttp_data_cb on_url;
    llhttp_data_cb on_status;
    llhttp_data_cb on_header_field;
    llhttp_data_cb on_header_value;

    /* Possible return values:
     * 0  - Proceed normally
     * 1  - Assume that request/response has no body, and proceed to parsing the
     *      next message
     * 2  - Assume absence of body (as above) and make `llhttp_execute()` return
     *      `HPE_PAUSED_UPGRADE`
     * -1 - Error
     * `HPE_PAUSED`
     */
    llhttp_cb      on_headers_complete;

    llhttp_data_cb on_body;

    /* Possible return values 0, -1, `HPE_PAUSED` */
    llhttp_cb      on_message_complete;

    /* When on_chunk_header is called, the current chunk length is stored
     * in parser->content_length.
     * Possible return values 0, -1, `HPE_PAUSED`
     */
    llhttp_cb      on_chunk_header;
    llhttp_cb      on_chunk_complete;
};

/* Initialize the parser with specific type and user settings */
void llhttp_init(llhttp_t* parser, llhttp_type_t type,
                 const llhttp_settings_t* settings);

/* Initialize the settings object */
void llhttp_settings_init(llhttp_settings_t* settings);

/* Parse full or partial request/response, invoking user callbacks along the
 * way.
 *
 * If any of `llhttp_data_cb` returns errno not equal to `HPE_OK` - the parsing
 * interrupts, and such errno is returned from `llhttp_execute()`. If
 * `HPE_PAUSED` was used as a errno, the execution can be resumed with
 * `llhttp_resume()` call.
 *
 * In a special case of CONNECT/Upgrade request/response `HPE_PAUSED_UPGRADE`
 * is returned after fully parsing the request/response. If the user wishes to
 * continue parsing, they need to invoke `llhttp_resume_after_upgrade()`.
 *
 * NOTE: if this function ever returns a non-pause type error, it will continue
 * to return the same error upon each successive call up until `llhttp_init()`
 * is called.
 */
llhttp_errno_t llhttp_execute(llhttp_t* parser, const char* data, size_t len);

/* This method should be called when the other side has no further bytes to
 * send (e.g. shutdown of readable side of the TCP connection.)
 *
 * Requests without `Content-Length` and other messages might require treating
 * all incoming bytes as the part of the body, up to the last byte of the
 * connection. This method will invoke `on_message_complete()` callback if the
 * request was terminated safely. Otherwise a error code would be returned.
 */
llhttp_errno_t llhttp_finish(llhttp_t* parser);

/* Returns `1` if the incoming message is parsed until the last byte, and has
 * to be completed by calling `llhttp_finish()` on EOF
 */
int llhttp_message_needs_eof(const llhttp_t* parser);

/* Returns `1` if there might be any other messages following the last that was
 * successfully parsed.
 */
int llhttp_should_keep_alive(const llhttp_t* parser);

/* Make further calls of `llhttp_execute()` return `HPE_PAUSED` and set
 * appropriate error reason.
 *
 * Important: do not call this from user callbacks! User callbacks must return
 * `HPE_PAUSED` if pausing is required.
 */
void llhttp_pause(llhttp_t* parser);

/* Might be called to resume the execution after the pause in user's callback.
 * See `llhttp_execute()` above for details.
 *
 * Call this only if `llhttp_execute()` returns `HPE_PAUSED`.
 */
void llhttp_resume(llhttp_t* parser);

/* Might be called to resume the execution after the pause in user's callback.
 * See `llhttp_execute()` above for details.
 *
 * Call this only if `llhttp_execute()` returns `HPE_PAUSED_UPGRADE`
 */
void llhttp_resume_after_upgrade(llhttp_t* parser);

/* Returns the latest return error */
llhttp_errno_t llhttp_get_errno(const llhttp_t* parser);

/* Returns the verbal explanation of the latest returned error.
 *
 * Note: User callback should set error reason when returning the error. See
 * `llhttp_set_error_reason()` for details.
 */
const char* llhttp_get_error_reason(const llhttp_t* parser);

/* Assign verbal description to the returned error. Must be called in user
 * callbacks right before returning the errno.
 *
 * Note: `HPE_USER` error code might be useful in user callbacks.
 */
void llhttp_set_error_reason(llhttp_t* parser, const char* reason);

/* Returns the pointer to the last parsed byte before the returned error. The
 * pointer is relative to the `data` argument of `llhttp_execute()`.
 *
 * Note: this method might be useful for counting the number of parsed bytes.
 */
const char* llhttp_get_error_pos(const llhttp_t* parser);

/* Returns textual name of error code */
const char* llhttp_errno_name(llhttp_errno_t err);

/* Returns textual name of HTTP method */
const char* llhttp_method_name(llhttp_method_t method);


/* Enables/disables lenient header value parsing (disabled by default).
 *
 * Lenient parsing disables header value token checks, extending llhttp's
 * protocol support to highly non-compliant clients/server. No
 * `HPE_INVALID_HEADER_TOKEN` will be raised for incorrect header values when
 * lenient parsing is "on".
 *
 * **(USE AT YOUR OWN RISK)**
 */
void llhttp_set_lenient(llhttp_t* parser, int enabled);

#ifdef __cplusplus
}  /* extern "C" */
#endif
#endif  /* INCLUDE_LLHTTP_API_H_ */

#endif  /* INCLUDE_LLHTTP_H_ */
